Osteolepiforms and the ancestry of tetrapods


Fossil discoveries1,2,3,4,5,6,7 and improved phylogenies3,4,5,7 have greatly improved our understanding of the origin of tetrapods, making it possible to reconstruct sequences of character change leading to tetrapod morphologies5,7 and to tentatively identify the genetic basis for some of these changes8,9. However, progress has centred on the upper part of the Tetrapodomorpha5 which is occupied by Devonian tetrapods such as Acanthostega1,2,5 and Ichthyostega1. Few advances have been made in improving our understanding of the lower, ‘fish’ part of the group, beyond establishing Elpistostegalia, Osteolepiformes and Rhizodontida as progressively more primitive constituents10,11,12,13. It has not been convincingly confirmed or disproved that the Osteolepiformes, a diverse but structurally uniform group that is central to the debate about tetrapod origins14,15,16,17, is monophyletic relative to tetrapods (that is, a single side branch on the tetrapod lineage). The earliest steps of the fish–tetrapod transition have thus remained poorly resolved. Here we present the first detailed analysis of the lower part of the Tetrapodomorpha, based on 99 characters scored for 29 taxa. We show that both the Osteolepiformes as a whole and their constituent group Osteolepididae are paraphyletic to tetrapods (that is, each comprises a section of the tetrapod lineage with several side branches), and that their ‘uniting characters’ are attributes of the tetrapodomorph stem lineage. The supposedly discredited idea of osteolepiforms as tetrapod ancestors14,15,16,17 is, in effect, supported by our analysis. Tetrapod-like character complexes evolved three times in parallel within the Tetrapodomorpha.

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Figure 1: Previous osteolepiform phylogenies.
Figure 2: New phylogeny of the tetrapodomorph stem group (consensus of 9 trees, based on 99 characters scored for 29 taxa).
Figure 3: Ancestral characters for clade Elpistostegalia+Tetrapoda.
Figure 4: Parallel evolution in the tetrapod stem group, inferred from the phylogeny in Fig. 2.


  1. 1

    Coates, M. I. & Clack J. A. Polydactyly in the earliest known tetrapod limbs. Nature 347, 66–69 (1990).

    ADS  Article  Google Scholar 

  2. 2

    Clack, J. A. Earliest known tetrapod braincase and the evolution of the stapes and fenestra ovalis. Nature 369, 392–394 (1994).

    ADS  Article  Google Scholar 

  3. 3

    Ahlberg, P. E. Elginerpeton pancheni and the earliest tetrapod clade. Nature 373, 420–425 (1995).

    ADS  CAS  Article  Google Scholar 

  4. 4

    Lebedev, O. A. & Coates, M. I. The postcranial skeleton of the Devonian tetrapod Tulerpeton curtum Lebedev. Zool. J. Linn. Soc. 114, 307–348 (1995).

    Article  Google Scholar 

  5. 5

    Coates, M. I. The Devonian tetrapod Acanthostega gunnari Jarvik: postcranial anatomy, basal tetrapod interrelationships and patterns of skeletal evolution. Trans. R. Soc. Edinb. Earth Sci. 87, 363–421 (1996).

    Article  Google Scholar 

  6. 6

    Ahlberg, P. E., Clack, J. A. & Lukševičs, E. Rapid braincase evolution between Panderichthys and the earliest tetrapods. Nature 381, 61–64 (1996).

    ADS  CAS  Article  Google Scholar 

  7. 7

    Ahlberg, P. E. Postcranial stem tetrapod remains from the Devonian of Scat Craig, Morayshire, Scotland. Zool. J. Linn. Soc. 122, 99–141 (1998).

    Article  Google Scholar 

  8. 8

    Shubin, N. The evolution of paired fins and the origin of tetrapod limbs. Evol. Biol. 28, 39–85 (1995).

    Article  Google Scholar 

  9. 9

    Shubin, N., Tabin, C. & Carroll, S. Fossils, genes and the evolution of animal limbs. Nature 388, 638–648 (1997).

    ADS  Article  Google Scholar 

  10. 10

    Schultze, H.-P. Dipnoans as sarcopterygians. J. Morphol. 1 (Suppl.), 39–74 (1986).

    Article  Google Scholar 

  11. 11

    Long, J. A. Anew rhizodontiform fish from the Early Carboniferous of Victoria, Australia, with remarks on the phylogenetic position of the group. J. Vert. Palaeontol. 9, 1–17 (1989).

    Article  Google Scholar 

  12. 12

    Cloutier, R. & Ahlberg, P. E. in Interrelationships of Fishes (eds Stiassny, M. L. J., Parenti, L. R. & Johnson, G. D.) 445–479 (Academic, San Diego, (1996).

    Google Scholar 

  13. 13

    Johanson, Z. & Ahlberg, P. E. Acomplete primitive rhizodont from Australia. Nature 394, 569–572 (1998).

    ADS  CAS  Article  Google Scholar 

  14. 14

    Andrews, S. M. & Westoll, T. S. The postcranial skeleton of Eusthenopteron foordi Whiteaves. Trans. R. Soc. Edinb. 68, 207–329 (1970).

    Article  Google Scholar 

  15. 15

    Andrews, S. M. & Westoll, T. S. The postcranial skeleton of rhipidistian fishes excluding Eusthenopteron. Trans. R. Soc. Edinb. 68, 391–489 (1970).

    Article  Google Scholar 

  16. 16

    Jarvik, E. Basic Structure and Evolution of Vertebrates Vol. 1(Academic, New York, (1980)).

    Google Scholar 

  17. 17

    Rackoff, J. S. in The Terrestrial Environment and the Origin of Land Vertebrates (ed. Panchen, A. L.) 255–292 (Academic, London, (1980)).

    Google Scholar 

  18. 18

    Rosen, D. E., Forey, P. L., Gardiner, B. G. & Patterson, C. Lungfishes, tetrapods, palaeontology, and plesiomorphy. Bull. Am. Mus. Nat. Hist. 167, 159–276 (1981).

    Google Scholar 

  19. 19

    Holmes, E. B. Are lungfishes the sister group of tetrapods? Biol. J. Linn. Soc. 25, 379–397 (1985).

    Article  Google Scholar 

  20. 20

    Panchen, A. L. & Smithson, T. S. Character diagnosis, fossils and the origin of tetrapods. Biol. Rev. Cambridge Phil. Soc. 62, 341–438 (1987).

    Article  Google Scholar 

  21. 21

    Young, G. C., Long, J. A. & Ritchie, A. Crossopterygian fishes from the Devonian of Antarctica: systematics, relationships and biogeographic significance. Rec. Austr. Mus. 14 (Suppl.), 1–77 (1992).

    Google Scholar 

  22. 22

    Chang, M.-M. & Yu, X. Reexamination of the relationship of Middle Devonian osteolepids–fossil characters and their interpretations. Am. Mus. Novit. 3189, 1–20 (1997).

    Google Scholar 

  23. 23

    Vorobyeva, E. I. 1977. Morphology and nature of evolution of crossopterygian fishes. Trudy Paleontol. Inst. 94, 1–239 (1977).

    Google Scholar 

  24. 24

    Lebedev, O. A. Morphology of a new osteolepidid fish from Russia. Bull. Mus. Nat. Hist. Nat. C 17, 287–341 (1995).

    Google Scholar 

  25. 25

    Long, J. A., Barwick, R. E. & Campbell, K. S. W. Osteology and functional morphology of the osteolepiform fish Gogonasus andrewsae Long, 1985, from the Upper Devonian Gogo Formation, Western Australia. Rec. West. Aust. Mus. 53 (Suppl.), 1–89 (1997).

    Google Scholar 

  26. 26

    Andrews, S. M. Rhizodont crossopterygian fish from the Dinantian of Foulden, Berwickshire, Scotland, with a re-evaluation of this group. Trans. R. Soc. Edinb. Earth Sci. 76, 67–95 (1985).

    Article  Google Scholar 

  27. 27

    Ahlberg, P. E. & Johanson, Z. Send tristichopterid (Sarcopterygii, Osteolepiformes) from the Upper Devonian of Canowindra, New South Wales, Australia, and phylogeny of the Tristichopteridae. J. Vert. Palaeontol. 17, 653–673 (1997).

    Article  Google Scholar 

  28. 28

    Vorobyeva, E. I. & Schultze, H.-P. in Origins of the Higher Groups of Tetrapods: Controversy and Consensus (eds Schultze, H.-P. & Trueb, L.) 68–109 (Cornell Univ., Ithaca, (1991)).

    Google Scholar 

  29. 29

    Johanson, Z. & Ahlberg, P. E. New tristichopterid (Osteolepiformes: Sarcopterygii) from the Mandagery Sandstone (Famennian) near Canowindra, N. S. W., Australia. Trans. R. Soc. Edinb. Earth Sci. 88, 39–68 (1997).

    Article  Google Scholar 

  30. 30

    Chang, M.-M. & Min, Z. Anew Middle Devonian osteolepid from Qujing, Yunnan. Mem. Ass. Australasian Palaeontol. 15, 183–198 (1993).

    Google Scholar 

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We thank the Australian Museum for their award of a Visiting Fellowship to P.E.A., E. Mark-Kurik for access to material of Thursius estonicus, J. Jeffery for information about rhizodonts and Academic Press for Figs 3a–c, 4a.

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Correspondence to Per E. Ahlberg.

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Ahlberg, P., Johanson, Z. Osteolepiforms and the ancestry of tetrapods. Nature 395, 792–794 (1998). https://doi.org/10.1038/27421

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